1996–1999 Yamaha Big Bear 2x4 YFM350UH Service Manual (P/N LIT-11616-10–08, 4UH-28197-20)

• Model and document identity: Covers the Yamaha Big Bear 2x4 YFM350UH service build, with specification tables headed YFM350U and regional model codes 4UH1 (USA), 4UH2 (Canada), 4UH3 (Europe), and 4VT1 (Australia). The PDF contains 315 pages. Yamaha publication numbers are LIT-11616-10-08 and 4UH-28197-20, first edition, August 1995.
• Engine repair: Documents engine removal and remounting, recoil-starter service, cylinder-head and cylinder work, piston and ring inspection, camshaft/rocker-arm/valve repair, timing-chain and CDI-rotor service, crankcase separation, crankshaft and balancer inspection, oil-pump work, clutch service, and transmission reassembly and adjustment.
• Carburetion and periodic inspection: Covers Mikuni BTM32SH carburetor removal, disassembly, inspection, assembly, installation, and fuel-level adjustment, along with valve-clearance and timing-chain checks, idle and throttle setup, speed-limiter adjustment, ignition-timing and compression checks, clutch adjustment, air-filter service, oil changes, toe-in, and shock settings.
• Drivetrain repair: Includes middle drive and driven gear removal, damper and universal-joint service, shim selection, gear-lash measurement and adjustment, plus rear axle, final-drive pinion and ring gear, and drive-shaft troubleshooting, disassembly, inspection, reassembly, and installation.
• Chassis and brake work: Details wheel service, the hydraulic front drum-brake master and wheel cylinders, brake pipes and hoses, system bleeding, rear drum-brake repair, steering-shaft and tie-rod work, front arms and shock absorbers, and rear shock/swingarm inspection and installation.
• Electrical diagnosis: Supplies five named circuit diagrams for the ignition, electric-starting, charging, lighting, and signal systems, together with starting-circuit operation, starter-motor overhaul, component test charts, and fault tracing for no-spark, no-crank, no-charge, lighting, indicator, horn, and oil-temperature faults. The separately listed YFM350U wiring diagram is not included in this PDF.

Regional Build Identification

The powertrain specification identifies an air-cooled 348 cc SOHC single with electric and recoil starting, wet-sump lubrication, a centrifugal automatic clutch, shaft drive, a constant-mesh five-speed transmission, reverse, and a high/low sub-transmission.

Engine starting numbers are 4UH-000101 (USA), 4UH-013101 (Canada), 4UH-015101 (Europe), and 4VT-000101 (Australia). The European frame starts at 4UH-015101, while the USA, Canadian, and Australian VIN patterns are also printed in the manual. These identifiers let a buyer match the publication to the machine before regional parts or repair procedures are selected.

Regional coverage goes beyond model labels. Separate cable-routing sections are supplied for USA/Canada/Europe and Australia. The carburetor table identifies 3HN 00 for USA/Canada/Europe and 4UM 00 for Australia; the specification pages also distinguish fuel-tank capacity, dimensions, spark plugs, idle settings, headlamp and indicator-bulb ratings, horn equipment, and related routing details. One clear example is the listed fuel capacity: 10 L for USA/Canada/Europe and 13.5 L for Australia.

Factory Procedures, Views, and Service Data

Exploded views precede the related disassembly work. Useful examples include the carburetor assembly, crankshaft/middle-drive-axle/transmission group, primary and secondary clutch, middle-gear damper and universal joint, rear axle/final-drive gear set, and hydraulic front-brake assembly. The specification chapter adds engine lubrication diagrams and regional cable-routing drawings.

The special-tool section gives alternate Yamaha tool numbers by country and explains their use. Examples include the valve-adjusting tool YM-08035 / 90890-05260, flywheel puller YM-01404 / 90890-01404, crankcase separating tool YU-01135-A / 90890-01135, gear-lash measurement tool YM-01231 / 90890-01231, and final-drive-shaft bearing-retainer wrench YM-04050 / 90890-04050. Supporting data covers component-specific torque tables, clearances, wear limits, lubrication points, capacities, carburetor calibration, starter and charging specifications, and electrical resistance tests.

Troubleshooting and Repair Notes

The final troubleshooting chapter separates starting failure into fuel, electrical, and compression causes, then covers poor idle, poor medium- and high-speed performance, drivetrain noise, hard shifting, gear jump-out, clutch slip or drag, overheating, poor braking, shock-absorber malfunction, unstable handling, and lighting faults. Chapter 8 uses step-by-step diagnostic charts to isolate circuit and component faults rather than offering wiring diagrams alone.

Do not spin cleaned bearings with compressed air; Yamaha warns that this damages the bearing surfaces. After middle-gear reassembly, too little gear lash is described as extremely destructive to the gear teeth, so an abnormal whine during the verification ride calls for immediate shutdown. Internal front-brake parts must be cleaned with new brake fluid rather than solvent, which can swell and distort the seals.

Engine, brake, steering, and drivetrain repair should be performed by a qualified technician or an experienced owner equipped to follow the Yamaha procedures, warnings, and inspection requirements.